Integrated circuit (IC) chips dissipate heat that must be transferred away from the IC chip to better ensure that the operating temperature of the IC chip remains at or below a maximum safe operating temperature, which is typically defined by the IC chip manufacturer. The maximum safe operating temperature of many IC chips is equal to or greater than the ambient temperature of the environment in which the IC chips operate. Heat sinks and/or air cooling systems may be used to transfer excess heat away from the IC so that the operating temperature of the IC chip is maintained at a safe level.
FIG. 1 shows a typical prior art IC chip package design. IC chip 101 has an operating temperature that is greater than or equal to the ambient temperature. The IC chip package 100 includes a substrate 103 to which IC chip 101 is attached. Bond wires 102 are connected between IC chip 101 and conductors (not shown) disposed in the substrate 103 that lead to the I/O pins 105. Lid 104 covers the cavity in which IC chip 101 is placed and hermetically seals the cavity from the ambient air. Flow arrows 106 indicate that heat flows from IC chip 101 to the ambient air outside of the IC chip package 100. When the operating temperature of IC chip 101 is greater than the ambient temperature of the surrounding environment, it is desirable to have as many thermal paths away from IC chip 101 such that sufficient heat transfer may take place.
For some IC chips it is desirable to reduce the operating temperature below the ambient temperature using some sort of cooling system. When the operating temperature is reduced below the ambient temperature, the direction of flow arrows 106 reverses such that the heat of the ambient air acts to heat IC chip 101. Therefore, a reduction in the number of thermal paths between IC chip 101 and the ambient air is desirable to improve the efficiency of the cooling system.
The prior art discloses that one method for reducing the number of thermal paths between IC chip 101 and the ambient environment outside of IC chip package 100 is to create a vacuum between IC chip 101 and the ambient environment, which isolates IC chip 101 from the ambient environment. However, a typical prior art method for creating a vacuum requires surrounding the entire IC chip package 100 with an evacuated chamber. This solution requires a large amount of printed circuit board space in a computer system. Further, prior cooling systems also typically require a significant amount of printed circuit board space. It would be desirable to provide an integrated circuit package that thermally isolates the IC chip from the ambient and that has an internal cooling device for cooling the integrated circuit so that the amount of printed circuit board space required to cool the IC chip is reduced.